cells: better perfs on invalid cells report (#40252)

combo/data/models.py

@@ -688,7 +688,7 @@ class CellBase(six.with_metaclass(CellMeta, models.Model)):
         return cell_types
 
     @classmethod
-    def get_cells(cls, cell_filter=None, skip_cell_cache=False, prefetch_validity_info=False, select_related=None, **kwargs):
+    def get_cells(cls, cell_filter=None, skip_cell_cache=False, prefetch_validity_info=False, select_related=None, load_contenttypes=False, **kwargs):
         """Returns the list of cells of various classes matching **kwargs"""
         cells = []
         pages = []
@@ -712,6 +712,9 @@ class CellBase(six.with_metaclass(CellMeta, models.Model)):
                     break
             else:
                 cell_classes = [get_cell_class(x) for x in cell_types]
+        if load_contenttypes:
+            # populate ContentType cache
+            ContentType.objects.get_for_models(*cell_classes)
         for klass in cell_classes:
             if klass is None:
                 continue

combo/manager/views.py

@@ -97,7 +97,8 @@ def invalid_cell_report(request):
     invalid_cells = CellBase.get_cells(
         select_related={'__all__': ['page']},
         page__snapshot__isnull=True,
-        validity_info__invalid_since__isnull=False)
+        validity_info__invalid_since__isnull=False,
+        load_contenttypes=True)
     invalid_cells = [c for c in invalid_cells if c.placeholder and not c.placeholder.startswith('_')]
     invalid_cells.sort(key=attrgetter('page.order', 'page.pk', 'order'))
     context = {

tests/test_public.py

@@ -181,7 +181,7 @@ def test_page_footer_acquisition(app):
         assert resp.text.count('BAR2FOO') == 1
         queries_count_third = len(ctx.captured_queries)
         # +2 for validity info of parent page
-        assert queries_count_third == queries_count_second + 2
+        assert queries_count_third == queries_count_second + 1
 
     with CaptureQueriesContext(connection) as ctx:
         resp = app.get('/second/third/fourth/', status=200)
@@ -189,7 +189,7 @@ def test_page_footer_acquisition(app):
         assert resp.text.count('BAR2FOO') == 1
         queries_count_fourth = len(ctx.captured_queries)
         # +1 for get_parents_and_self()
-        assert queries_count_fourth == queries_count_second + 2 + 1
+        assert queries_count_fourth == queries_count_second + 1 + 1
 
     # check footer doesn't get duplicated in real index children
     page6 = Page(title='Sixth', slug='sixth', template_name='standard', parent=page_index)